Hydropneumatic absorbing device



y ,1 z. OQKARAKASHJAN ETAL 3,193,112

HYDROPNEUMATIC ABSORBING DEVICE Filed Jan. 23, 1963 2 Sheets-Sheet 1#9020 2, y; xi .42 2

INVENTORS Z 0. KHiH/(ASHJAA/ 4. Z 77Mo6wuK E 6'. Mme/a4 No v July 6,1965 2. o. KARAKASHJAN ETAL 3, 93,112

HYDROPNEUMA'IIC ABSORBING DEVICE Filed Jan. 23, 1965 2 Sheets-Sheet 2 A.4 z ry 6 z r k 6' 4- g r .1 7 4 5 J! 22 7 .4 k a 4 I C B z I NV F 7 fl/A 4/ V A? 4 2 A United States Patent 3,193,112 RGPNEUMATHC ABSORBMJGDEVICE Zaven Oganezovich Karalrashjan, Dobroljubov Str. 18,

Apt. 46; Albert lsidorovich Timoshulr, llolshaja Pirogovskaja Sir.53/55, Apt. 114; and Fjodor Stepanovich Marlranov, Bolshoy Savinskylay-street 7, Apt. 4; all of Moscow, USSR.

Filed Jan. 23, 1963, Ser. No. 273,799 4 Claims. (Cl. 2213-43) Thisinvention relates to absorbing devices for absorbing kinetic energy ofrelatively movable bodies and more particularly automatic couplers forrailway rolling stock.

There exist hydropneumatic absorbing devices in which the absorption ofthe kinetic energy is effected due to the cooperation of the pneumaticresilient members, namely, the buffers and the hydraulic absorbers. Inparticular, in buffers of the railway rolling stock use is made ofhydro-pneumatic devices comprising a hydraulic cylinder in which thepiston is provided with a by-pass gauged opening, and the space abovethe piston is separated from the gas chamber of the buffer by a floatingpiston. The piston of the hydraulic cylinder is connected directly tothe cylinder of the gas chamber.

All of the known absorbing devices are ineffective under slowlyincreasing load conditions, as when the piston moves slowly in thehydraulic cylinder which may take place during smooth starting of therolling stock or with the rolling stock moving over a long gradient, thehydraulic resistance decreases in direct proportion to the square of theflow rate of the fluid. This arrangement renders ineffective theexisting devices used for automatic couplers for railway rolling stock.

Attempts previously made to overcome these difficulties and shortcomingshave proved to be inadequate.

The present invention provides an assemblage which eliminates theshortcomings of existing absorbing devices.

This invention is intended specially for automatic couplers for railwayrolling stock.

An object of this invention is to provide means for dampening the shocksand impacts arising at relatively slow movement of the piston of theassembly, namely,

'at starting or the moving of the rolling stock over long drawings, inwhich drawings:

FIG. 1 is an elevational view partly in cross-section illustrating thepresent invention.

FIG. 2 is a fragmentary vertical cross-sectional view of FIG. 1illustrating the piston.

FIG. 3 is a fragmentary view of the components of the throttling valve.

FIG. 4 is a vertical cross-sectional view partly in elevation showingthe relationship of the components at the initiation of the powerstroke.

FIG. 5 is a view generally similar to FIG. 4 showing 3,193,1l2 PatentedJuly 6, 1965 the relationship of the components at the intermediatestage of the power stroke.

FIG. 6 is a view similar to FIG. 4 showing the relationship of thecomponents at the initial return stroke, and

FIG. 7 is a diagrammatic view of the performance of the absorbingdevice.

As shown in FIG. 1, the basic component of the absorbing device includesa cylindrical casing 1 having an open end and a base end 2. A piston 3mounted within the casing is operably attached to an axiallydisplaceable cylinder 4 extending into the casing from the open end. Afloating piston 5 is located in the cylinder 4 and a second floatingpiston 6 is positioned within the casing 1 in proximity to the base end2.

A washer or ring 8 is fixed to the interior of the casing 1 by gasketrings 9 and 10 and such washer limits the movement of the piston 3towards the base end and of the floating piston 6 towards the open end.

It will be seen that the casing 1 is provided with three separatechambers A, B and C, respectively. The chamber A is filled withcompressed gas, such as air, at an initial pressure of about 6 kg./cm.chamber B with effective fluid, such as oil, and chamber C with aneutral gas, such as nitrogen, at an initial pressure of 60 kg./cm.

The piston 3 is provided with by-pass gauged openings 11 and centralby-pass slots 12, as best shown in FIG. 2. Flange 13 of the piston 3(FIG. 3) includes openings 14 through which the fluid enters the chamberB The return stroke throttling valve 15 is defined by a ring freelymounted within the casing and is provided with a plurality of axialopenings 16 connected to circular groove 33. A packing for space Bincludes a circular cage 17 having double sided grooves 34 fitted withgasket or sealing rings 18 and a hydraulic seal is achieved by twogrooves 19 which communicate with space B via longitudinal channel 20.

A valve 21 is built into the closed end of the cylinder 4 for feedingcompressed air into the chamber A. A similar valve 35 is provided forthe base end 2 of the casing 1 for feeding neutral gas into the chamberC. A rod 7 extends through the washer 8 and coacts at one end thereofwith the floating piston 6 in chamber C. The rod 7 is formed with ahollow reduced extension 22. and on which the piston 3 is freelymounted. The length of the reduced extension 22 is such as to assure thepossibility of preliminary movement of the piston 3 along the relativelyimmovable rod 7 at the initial power stroke of the assemblage. A safetyvalve defined by a valve body 23, a set of disc springs 24 and a stopnut 25 is mounted within the extension 22 and the interior of theextension is connected to the chamber B behind the piston 32 by channel26 in the rod 7.

On the opposite end of the rod 7 is a stop head 27. The floating piston6 has a central chamber D for additional small floating piston 28 andthe extreme position of the latter piston is determined by a bolt 29.The chamber D forward of the small piston is filled with oil and isconnected to peripheral grooves 31 by channels 30. The oil in thegrooves Sll forms a hydraulic seal which in combination with rubbergasket or seal rings 32 eliminates the possibility of gas leakage fromthe chamber C.

The operation of the absorbing device is as follows: At the initialpower stroke such as when the trainstarts 7 A a v 3 or at braking whilemoving, the cylinder 4 under the action of the movable members of theautomatic coupler begins to move in the direction shown by the arrow inthe FIG. 4. At the initial power stroke, the piston 3 moves freely alongthe immovable rod 7. At this time, the effective fluid flows from. thechamber B behind the piston through the openings 11, slots 12 andopenings 14 into the spaces B and B thus overcoming the resistance ofthe compressed air filling the chamber .A. The effective fluid enteringthe space B affects the floate ing piston 5 within the cylinder' l (FIG.'5).

On further movement, the piston 3 reaches shoulder- 36 of theextension'22 and the head 27 of the rod 7 starts to affect the floatingpiston 6 in the chamber C. The

shoulder 36 covers the slots 12 (FIG.'5) and thus further increases thehydraulic resistance. To move the piston 6, it is necessary to overcomethe considerable (compared with the resistance of the compressed air inenergy transforms into heat energy as early as the power stroke(hydraulic losses and apart of work spent on heating the compressed gas,the pressure of which at the end of the power stroke increases 5-12times in each chamber). A considerable part of the energy is absorbedduring the return stroke, which is promoted by the returnthe chamber A)resistance of the compressed gas in the chamber C dueto which it isassured a substantial increase in the effort of the absorbing. device.At thereturn stroke (FIG. 6) which is effected under the action of theelastic forces of the compressed gases in the cham bers A and C, thepiston 3 with. the cylinder 4 and the piston 6 move in the directionopposite to that shown by the arrow (FIG. 6). V

Under the influence of liquid contained within the space B there iseffected a pressing of the ring 15 against the flange 13 of the piston 3(FIGURE 3). The effectivefluid flOWs from. the spaces B and B back intothe chamber B through the openings 1 1, 16 and 14. Due to the fact thatthe fluid must overcome the resistance of the opening 16 in the. ring15, this significantly increases hydraulic re.- sistance whereby animpact at the return stroke is eliminated. i l

At themoment when the piston 6 rests against the washer or ring 8, itstops and the piston 3 together with the cylinder 4 is separated fromtheshoulder 36 whereby the slots 12 are opened for fluid flow and thepiston 3 continues its return movement to the initial position of thedevice. i V

In the case of slow starting, the flow rate of the fluid through theopenings 11 and 14 andslots 12 may be so small that the hydraulicresistance of the device will be rather negligible, In this case, thechamber C prevents closing of the device thereby ensuring damping of theshocks occurring at starting.

In the case of applying heavy impact loads the pressure of the effectivefluid in the chamber B may increase considerably This is prevented bythe safety valve in the hollow extension 22 of the rod-7; When the valveseats the fluid freely flows fromthe chamber B into the space B thuspreventing damage by excessive internal pressure.

The diagram shown in FIG. 7 illustrates the character of variation ofthe effort Q developed by the device 'during shunting and trainoperation, i.e. at car braking stroke throttle valve, ensuring aconsiderable increase of hydraulic resistance.

It should be noted that the present invention ensures effectiveoperation of the device under different operating conditions. Repeated,impacts of comparatively low force arising during train movement areconsiderably damped by the low pressure gas chamberA long before thehigh gas pressure chamber C comes into operation. Most of the energy ofthe impacts both during the power strokes and the return strokes isdissipated due to the hydraulic resistance developed during the flow ofthe 7 effective fluid through the by-pass openings and slots.

Heavy loads, both impact and comparatively slowly increasing ones, aretaken by the additional gas chamber. qThis prevents the members of theautomatic coupler as well as the frames of the rolling stock fromfailing because of fatigue due to the action of repeated alternat ingloa'ds and the effect ofloads causing stresses 'exceed- Ting theresistance ofthe materials of these members.

, This makes possible to prolong the operating life of the rolling stockand to increaseits working weight as well as the speed ofshunting-operations without any strengthening of the frames of the"carsand without any damage to thegoods carried by the cars.

., The inventionis'not to be confinedto any strict conformity to'th'eshowing inthe drawings, but changes .or modifications may be madetherein so long as such changes or modifications mark no materialdeparture fromthespirit and scope of the appended claims.

What we claim'is: 7 a

1. A hydro-pneumatic absorbing device for absorbing kinetic energyofbodies'being in relative motion and particularly for automatic couplersfor railway rolling stock, comprising a casing having a closed end andan open end, a cylinder mounted'for axial movement within the :casingand havinga closed end projectingbeyond the .open end of the casing-awasher secured within the casing; a piston rod extending through anopening in said washer, a piston mounted on saidrod operably connectedwith the cylinder, a" floating. piston, within said cylinder with thechamber providedbetween the floating piston and .the closed endconstituting a low pressure gas chamber,

. a second floating piston within said casing between the washer and theclosedfend coacting with said rod and the chamber provided between suchpiston and closed end constituting ayhigh pressure gas chamber, thechamber between the" piston mounted on said rod and the washer place onthe section 0-I. At the point I, the chamber C comes into operation andvariation of the effort developed by the latter is shown by the line b.The dynamic resistance increases only up to the point II, and then therate of movement begins to drop considerably. However, the resistance ofthe gas compressed in the chamber C which varies in accordance with theadiabatic law,

.sharply increases at the end of the stroke compensating for the drop ofthe hydraulic resistance, This. ensures effective operation of theabsorbing device. The law :of change of the total effort is representedby the curve d.

During the operation of the device a part of the kinetic constituting achamber for fluid, means providing an annularspace between said cylinderand easing adjacent the open end of the cylinder and said last namedpiston having gauged openings therein for the flow of fluid from{rhefluid chamber into said cylinder and into said annular space. 1 Y2.1 The absorbing device as claimed 'in claim 1, including arreturnstrokethrottling valve in said annular space and defined by a ringfreely mounted in said space provided with a plurality of openingsparallel to the longitudinal axis thereof and an end groove for the flowof fluid; and said piston having a flange in spaced rela- 'tion,to theringgserving asa stop on the return stroke of the piston. r I '3;Theabsorbing device as claimed in claim 1, in which the piston in saidhigh pressure gas chamber is, provided 5 6 sion on which said piston ismounted, port means in References Cited by the Examiner the rodproviding communication between the reduced UNITED STATES PATENTSextension and the fluid chamber, and a safety valve within the hollowextension and in communication with a space between the floating pistonin the low pressure gas cham- 5 her and the piston operative to admitfluid into such w space in the event of excessive pressure beingdeveloped DUGDND BOTZ Pnmary Examiner in the fluid chamber. LEOQUACKENBUSH, Examiner.

2,726,773 12/55 Fitz John 213-223 X 2,994,442 8/61 Frederick 213-43

1. A HYDRO-PNEUMATIC ABSORBING DEVICE FOR ABSORBING KINETIC ENERGY OFBODIES BEING IN RELATIVE MOTION AND PARTICULARLY FOR AUTOMATIC COUPLERSFOR RAILWAY ROLLING STOCK, COMPRISING A CASING HAVING A CLOSED END ANDAN OPEN END, A CYLINDER MOUNTED FOR AXIAL MOVEMENT WITHIN THE CASING ANDHAVING A CLOSED END PROJECTING BEYOND THE OPEN END OF THE CASING, AWASHER SECURED WITHIN THE CASING, A PISTON ROD EXTENDING THROUGH ANOPENING IN SAID WASHER, A PISTON MOUNTED ON SAID ROD OPERABLY CONNECTEDWITH THE CYLINDER, A FLOATING PISTON WITHIN SAID CYLINDER WITH THECHAMBERPROVIDED BETWEEN THE FLOATING PISTON AND THE CLOSED ENDCONSTITUTING A LOW PRESSURE GAS CHAMBER, A SECOND FLOATING PISTON WITHINSAID CASING BETWEEN THE WASHER AND THE CLOSED END COACTING WITH SAID RODAND THE CHAMBER PROVIDED BETWEEN SUCH PISTON AND CLOSED END CONSTITUTINGA HIGH PRESSURE GAS CHAMBER, THE CHAMBER BETWEEN THE PISTON MOUNTED ONSAID ROD AND THE WASHER CONSTITUTING A CHAMBER FOR FLUID, MEANSPROVIDING AN ANNULAR SPACE BETWEEN SAID CYLINDER AND CASING ADJACENT THEOPEN END OF THE CYLINDER AND SAID LAST NAMED PISTON HAVING GAUGEDOPENINGS THEREIN FOR THE FLOW OF FLUID FROM THE FLUID CHAMBER INTO SAIDCYLINDER AND INTO SAID ANNULAR SPACE.